Blackjack

This environment is part of the Atari environments. Please read that page first for general information.

Action Space	Discrete(4)
Observation Shape	(210, 160, 3)
Observation High	255
Observation Low	0
Import	gymnasium.make("ALE/Blackjack-v5")

For more Blackjack variants with different observation and action spaces, see the variants section.

Description

Blackjack is missing description documentation. If you are interested in writing up a description, please create an issue or PR with the information on the Gymnasium github.

Actions

Blackjack has the action space Discrete(4) with the table below lists the meaning of each action’s meanings. As Blackjack uses a reduced set of actions for v0, v4 and v5 versions of the environment. To enable all 18 possible actions that can be performed on an Atari 2600, specify full_action_space=True during initialization or by passing full_action_space=True to gymnasium.make.

Value	Meaning	Value	Meaning	Value	Meaning
0	NOOP	1	FIRE	2	UP
3	DOWN

Observations

Atari environment have two possible observation types, the observation space is listed below. See variants section for the type of observation used by each environment id.

• obs_type="rgb" -> observation_space=Box(0, 255, (210, 160, 3), np.uint8)

• obs_type="ram" -> observation_space=Box(0, 255, (128,), np.uint8)

Additionally, obs_type="grayscale" cause the environment return a grayscale version of the rgb array for observations with the observation space being Box(0, 255, (210, 160), np.uint8)

Variants

Blackjack has the following variants of the environment id which have the following differences in observation, the number of frame-skips and the repeat action probability.

Env-id	obs_type=	frameskip=	repeat_action_probability=
ALE/Blackjack-v5	"rgb"	4	0.25
ALE/Blackjack-ram-v5	"ram"	4	0.25

Difficulty and modes

It is possible to specify various flavors of the environment via the keyword arguments difficulty and mode. A flavor is a combination of a game mode and a difficulty setting. The table below lists the possible difficulty and mode values along with the default values.

Available Modes	Default Mode	Available Difficulties	Default Difficulty
[0]	0	[0, 1, 2, 3]	0

Version History

A thorough discussion of the intricate differences between the versions and configurations can be found in the general article on Atari environments.

• v5: Stickiness was added back and stochastic frameskipping was removed. The environments are now in the “ALE” namespace.

• v4: Stickiness of actions was removed

• v0: Initial versions release